MET molecular mechanisms and therapies in lung cancer

Targeting MET: Discovery of Small Molecule Inhibitors as Non-Small Cell Lung Cancer Therapy

MET has been considered as a promising drug target for the treatment of MET-dependent diseases, particularly non-small cell lung cancer (NSCLC). Small molecule MET inhibitors with mainly three types of binding modes (Ia/Ib, II, and III) have been developed. In this Review, we provide an overview of the structural features, activation mechanism, and dysregulation pathway of MET and summarize progress on the development and discovery strategies utilized for MET inhibitors as well as mechanisms of acquired resistance to current approved inhibitors. The insights will accelerate discovery of new generation MET inhibitors to overcome clinical acquired resistance.

Identification of a m6A-related ferroptosis signature as a potential predictive biomarker for lung adenocarcinoma

BACKGROUND

Both N6-methyladenosine (m⁶A) and ferroptosis-related genes are associated with the prognosis of lung adenocarcinoma. However, the predictive value of m⁶A-related ferroptosis genes remains unclear. Here, we aimed to identify the prognostic value of m⁶A-related ferroptosis genes in lung adenocarcinoma.

METHODS

Lung adenocarcinoma sample data were downloaded from the University of California Santa Cruz Xena and Gene Expression Omnibus databases. Spearman's correlation analysis was used to screen for m⁶A-related ferroptosis genes. Univariate Cox regression, Kaplan-Meier, and Lasso analyses were conducted to identify prognostic m⁶A-related ferroptosis genes, and stepwise regression was used to construct a prognostic gene signature. The predictive value of the gene signature was assessed using a multivariate Cox analysis. In the validation cohort, survival analysis was performed to verify gene signature stability. The training cohort was divided into high- and low-risk groups according to the median risk score to assess differences between the two groups in terms of gene set variation analysis, somatic mutations, and tumor immune infiltration cells.

RESULTS

Six m⁶A-related ferroptosis genes were used to construct a gene signature in the training cohort and a multivariate Cox analysis was conducted to determine the independent prognostic value of these genes in lung adenocarcinoma. In the validation cohort, Kaplan-Meier and receiver operating characteristic analyses confirmed the strong predictive power of this signature for the prognosis of lung adenocarcinoma. Gene set variation analysis showed that the low-risk group was mainly related to immunity, and the high-risk group was mainly related to DNA replication. Somatic mutation analysis revealed that the TP53 gene had the highest mutation rate in the high-risk group. Tumor immune infiltration cell analysis showed that the low-risk group had higher levels of resting CD4 memory T cells and lower levels of M0 macrophages.

CONCLUSION

Our study identified a novel m⁶A-related ferroptosis-associated six-gene signature (comprising SLC2A1, HERPUD1, EIF2S1, ACSL3, NCOA4, and CISD1) for predicting lung adenocarcinoma prognosis, yielding a useful prognostic biomarker and potential therapeutic target.

Updated Views in Targeted Therapy in the Patient with Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most frequent form of lung cancer and represents a set of histological entities that have an ominous long-term prognosis, for example, adenocarcinoma, squamous carcinoma and large cell carcinoma. Both small cell and non-small cell lung cancer are the main causes of oncological death and the oncological diseases with the highest incidence worldwide. With regard to clinical approaches for NSCLC, several advances have been achieved in diagnosis and treatment; the analysis of different molecular markers has led to the development of new targeted therapies that have improved the prognosis for selected patients. Despite this, most patients are diagnosed in an advanced stage, presenting a limited life expectancy with an ominous short-term prognosis. Numerous molecular alterations have been described in recent years, allowing for the development of therapies directed against specific therapeutic targets. The correct identification of the expression of different molecular markers has allowed for the individualization of treatment throughout the disease course, expanding the available therapeutic arsenal. The purpose of this article is to summarize the main characteristics of NSCLC and the advances that have occurred in the use of targeted therapies, thus explaining the limitations that have been observed in the management of this disease.

Recent Advances in Lung Cancer Therapy Based on Nanomaterials: A Review

Lung cancer is one of the commonest cancers with a significant mortality rate for both genders, particularly in men. Lung cancer is recognized as one of the leading causes of death worldwide, which threatens the lives of over 1.6 million people every day. Although cancer is the leading cause of death in industrialized countries, conventional anticancer medications are unlikely to increase patients' life expectancy and quality of life significantly. In recent years, there are significant advances in the development and applications of nanotechnology in cancer treatment. The superiority of nanostructured approaches is that they act more selectively than traditional agents. This progress led to the development of a novel field of cancer treatment known as nanomedicine. Various formulations based on nanocarriers, including lipids, polymers, liposomes, nanoparticles and dendrimers have opened new horizons in lung cancer therapy. The application and expansion of nano-agents lead to an exciting and challenging research era in pharmaceutical science, especially for the delivery of emerging anti-cancer agents. The objective of this review is to discuss the recent advances in three types of nanoparticle formulations for lung cancer treatments modalities, including liposomes, polymeric micelles, and dendrimers for efficient drug delivery. Afterward, we have summarized the promising clinical data on nanomaterials based therapeutic approaches in ongoing clinical studies.

Alterations in key signaling pathways in sinonasal tract melanoma. A molecular genetics and immunohistochemical study of 90 cases and comprehensive review of the literature

Sinonasal mucosal melanoma is a rare tumor arising within the nasal cavity, paranasal sinuses, or nasopharynx (sinonasal tract). This study evaluated 90 cases diagnosed in 29 males and 61 females with median age 68 years. Most tumors involved the nasal cavity and had an epithelioid morphology. Spectrum of research techniques used in this analysis includes targeted-DNA and -RNA next-generation sequencing, Sanger sequencing, fluorescence in situ hybridization and immunohistochemistry. Sinonasal melanomas were commonly driven by RAS (38/90, 42%), especially NRAS (n = 36) mutations and rarely (4/90, 4%) displayed BRAF pathogenic variants. BRAF/RAS mutants were more frequent among paranasal sinuses (10/14, 71%) than nasal (26/64, 41%) tumors. BRAF/RAS-wild type tumors occasionally harbored alterations of the key components and regulators of Ras-MAPK signaling pathway: NF1 mutations (1/17, 6%) or NF1 locus deletions (1/25, 4%), SPRED1 (3/25, 12%), PIK3CA (3/50, 6%), PTEN (4/50, 8%) and mTOR (1/50, 2%) mutations. These mutations often occurred in a mutually exclusive manner. In several tumors some of which were NRAS mutants, TP53 was deleted (6/48, 13%) and/or mutated (5/90, 6%). Variable nuclear accumulation of TP53, mirrored by elevated nuclear MDM2 expression was seen in >50% of cases. Furthermore, sinonasal melanomas (n = 7) including RAS/BRAF-wild type tumors (n = 5) harbored alterations of the key components and regulators of canonical WNT-pathway: APC (4/90, 4%), CTNNB1 (3/90, 3%) and AMER1 (1/90, 1%). Both, TERT promoter mutations (5/53, 9%) and fusions (2/40, 5%) were identified. The latter occurred in BRAF/RAS-wild type tumors. No oncogenic fusion gene transcripts previously reported in cutaneous melanomas were detected. Eight tumors including 7 BRAF/RAS-wild type cases expressed ADCK4::NUMBL cis-fusion transcripts. In summary, this study documented mutational activation of NRAS and other key components and regulators of Ras-MAPK signaling pathway such as SPRED1 in a majority of sinonasal melanomas.

CircSND1/miR-182-5p Axis Promotes Proliferative and Invasive Abilities of Thyroid Cancer via Binding Targeting MET

Objective. To monitor the impacts of circSND1 upon thyroid cancer (TC) tissues and cells and its mechanisms. Methods. Thiazole blue (MTT) was adopted to monitor the impacts of circSND1 upon the proliferative abilities of TPC-1 and SW1736 cells. 5-Bromodeoxyuridine (BrdU) combined with flow cytometry was adopted to monitor the impacts of circSND1 upon the DNA synthesis of TPC-1 and SW1736 cells. We adopted transwell experiment to examine the impacts of circSND1 on cell invasive abilities of TPC-1 and SW1736 cells. The mRNA quantitative levels of circSND1, miR-182-5p, and mesenchymal epidermal transformation factor (MET) in TC tissues were detected by qRT-PCR experiment. We also adopted luciferase assay to verify the targeting interaction between miR-182-5p and MET or miR-182-5p and circSND1. Results. CircSND1 mRNA and MET mRNA were upregulated in thyroid cancer tissues. MiR-182-5p quantification was attenuated in thyroid cancer tissues. Downregulation of circSND1 suppressed TC progression in vivo and in vitro. Furthermore, luciferase report assay uncovered that miR-182-5p was a direct binding target of circSND1 and MET was a direct binding target of miR-182-5p. Besides, circSND1 regulated MET expression and thyroid cancer cell function via binding miR-182-5p. Conclusion. Overexpression of circSND1 in TC tissues and cells facilitates TC tumorigenesis and metastasis via suppressing the quantitative level of miR-182-5p and inducing the upregulation of MET mRNA and protein expression, which expected to offer fresh clues for the administration of TC.

Identification of a prognostic ferroptosis-related lncRNA signature in the tumor microenvironment of lung adenocarcinoma

Ferroptosis is closely linked to various cancers, including lung adenocarcinoma (LUAD); however, the factors involved in the regulation of ferroptosis-related genes are not well established. In this study, we identified and characterized ferroptosis-related long noncoding RNAs (lncRNAs) in LUAD. In particular, a coexpression network of ferroptosis-related mRNAs and lncRNAs from The Cancer Genome Atlas (TCGA) was constructed. Univariate and multivariate Cox proportional hazards analyses were performed to establish a prognostic ferroptosis-related lncRNA signature (FerRLSig). We obtained a prognostic risk model consisting of 10 ferroptosis-related lncRNAs: AL606489.1, AC106047.1, LINC02081, AC090559.1, AC026355.1, FAM83A-AS1, AL034397.3, AC092171.5, AC010980.2, and AC123595.1. High risk scores according to the FerRLSig were significantly associated with poor overall survival (hazard ratio (HR) = 1.412, 95% CI = 1.271–1.568; P < 0.001). Receiver operating characteristic (ROC) curves and a principal component analysis further supported the accuracy of the model. Next, a prognostic nomogram combining FerRLSig with clinical features was established and showed favorable predictive efficacy for survival risk stratification. In addition, gene set enrichment analysis (GSEA) revealed that FerRLSig is involved in many malignancy-associated immunoregulatory pathways. Based on the risk model, we found that the immune status and response to immunotherapy, chemotherapy, and targeted therapy differed significantly between the high-risk and low-risk groups. These results offer novel insights into the pathogenesis of LUAD, including the contribution of ferroptosis-related lncRNAs, and reveal a prognostic indicator with the potential to inform immunological research and treatment.

Computational and in vitro characterization of ICY-5: A potential candidate promoting mitochondrial apoptosis via the c-MET and STAT3 pathways

Targeted chemotherapy remains the primary choice in controlling various forms of breast cancer (BC) due to its heterogenous gene expressions in various subtypes. In silico and in vitro evaluation of ICY-5, a novel arylidene analogue against c-MET, was performed. ICY-5 exhibited a docking score of -9.6 kcal/mol in inactive conformation and, - 8.6 kcal/mol in active conformation for c-MET. ICY-5 inhibited c-MET enzyme with an IC₅₀ of 34.34 nM. The compound effectively inhibited MDA-MB 231 and MCF-7 cell proliferation, with GI₅₀ values of 62.61 and 75.31 nM, respectively, and hepatocyte growth factor (HGF)/R c-MET phosphorylation with IC₅₀ s of 71.41 and 83.77 nM, respectively. ICY-5 dose-dependently inhibited HGF-induced transmigration, cell scattering, invasion and altered cell cycle. An increase in apoptotic populations of these cells, with a dose-dependent decease in phosphorylation of STAT3 protein was observed. Furthermore, ICY-5 upregulated the caspase-3, caspase-9, Bcl-2-associated X and survivin, and downregulated Bcl-2, vascular endothelial growth factor, matrix metalloproteinase-2 (MMP-2), and MMP-9 in both BC cell lines. In summary, ICY-5 exhibited excellent efficacy in BC cells, targeting c-MET/SAT-3-mediated mitochondrial apoptosis. Further research will be required to ascertain ICY-5 suitability as a targeted chemotherapeutic against multiple forms of BC.

Progress on treatment of MET signaling pathway in non-small cell lung cancer

MET activation includes gene mutation, amplification, and protein overexpression. Clinical evidence suggests that MET activation is both a primary oncogenic driver in lung cancer, and a secondary driver after acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). Several small molecule TKIs have already shown to be effective in the MET pathway. However, the activation form and the diagnostic criteria of MET oncogene are still controversial, especially in patients resistant to EGFR TKIs or ALK TKIs. With the development of new MET inhibitors, a quantity of emerging trials has focused on the mechanism of acquired resistance to MET TKIs and therapeutic strategies after resistance.

Identification of a novel glycolysis-related gene signature for predicting metastasis and survival in patients with lung adenocarcinoma

Background

Lung cancer (LC) is one of the most lethal and most prevalent malignant tumors, and its incidence and mortality are increasing annually. Lung adenocarcinoma (LUAD) is the most common pathological type of lung cancer. Several biomarkers have been confirmed by data excavation to be related to metastasis, prognosis and survival. However, the moderate predictive effect of a single gene biomarker is not sufficient. Thus, we aimed to identify new gene signatures to better predict the possibility of LUAD.

Methods

Using an mRNA-mining approach, we performed mRNA expression profiling in large LUAD cohorts (n = 522) from The Cancer Genome Atlas (TCGA) database. Gene Set Enrichment Analysis (GSEA) was performed, and connections between genes and glycolysis were found in the Cox proportional regression model.

Results

We confirmed a set of nine genes (HMMR, B4GALT1, SLC16A3, ANGPTL4, EXT1, GPC1, RBCK1, SOD1, and AGRN) that were significantly associated with metastasis and overall survival (OS) in the test series. Based on this nine-gene signature, the patients in the test series could be divided into high-risk and low-risk groups. Additionally, multivariate Cox regression analysis revealed that the prognostic power of the nine-gene signature is independent of clinical factors.

Conclusion

Our study reveals a connection between the nine-gene signature and glycolysis. This research also provides novel insights into the mechanisms underlying glycolysis and offers a novel biomarker of a poor prognosis and metastasis for LUAD patients.

Identification and Characterization of Oncogenic SOS1 Mutations in Lung Adenocarcinoma

Lung adenocarcinomas are characterized by mutations in the receptor tyrosine kinase (RTK)/Ras/Raf pathway, with up to 75% of cases containing mutations in known driver genes. However, the driver alterations in the remaining cases are yet to be determined. Recent exome sequencing analysis has identified SOS1, encoding a guanine nucleotide exchange factor, as significantly mutated in lung adenocarcinomas lacking canonical oncogenic RTK/Ras/Raf pathway mutations. Here, we demonstrate that ectopic expression of lung adenocarcinoma-derived mutants of SOS1 induces anchorage-independent cell growth in vitro and tumor formation in vivo. Biochemical experiments suggest that these mutations lead to overactivation of the Ras pathway, which can be suppressed by mutations that disrupt either the Ras-GEF or putative Rac-GEF activity of SOS1. Transcriptional profiling reveals that the expression of mutant SOS1 leads to the upregulation of MYC target genes and genes associated with Ras transformation. Furthermore, we demonstrate that an AML cancer cell line harboring a lung adenocarcinoma-associated mutant SOS1 is dependent on SOS1 for survival and is also sensitive to MEK inhibition. Our work provides experimental evidence for the role of SOS1 as an oncogene and suggests a possible therapeutic strategy to target SOS1-mutated cancers. IMPLICATIONS: This study demonstrates that SOS1 mutations found in lung adenocarcinoma are oncogenic and that MEK inhibition may be a therapeutic avenue for the treatment of SOS1-mutant cancers.

Bayesian Neural Networks for Selection of Drug Sensitive Genes

Recent advances in high-throughput biotechnologies have provided an unprecedented opportunity for biomarker discovery, which, from a statistical point of view, can be cast as a variable selection problem. This problem is challenging due to the high-dimensional and non-linear nature of omics data and, in general, it suffers three difficulties: (i) an unknown functional form of the nonlinear system, (ii) variable selection consistency, and (iii) high-demanding computation. To circumvent the first difficulty, we employ a feed-forward neural network to approximate the unknown nonlinear function motivated by its universal approximation ability. To circumvent the second difficulty, we conduct structure selection for the neural network, which induces variable selection, by choosing appropriate prior distributions that lead to the consistency of variable selection. To circumvent the third difficulty, we implement the population stochastic approximation Monte Carlo algorithm, a parallel adaptive Markov Chain Monte Carlo (MCMC) algorithm, on the OpenMP platform which provides a linear speedup for the simulation with the number of cores of the computer. The numerical results indicate that the proposed method can work very well for identification of relevant variables for high-dimensional nonlinear systems. The proposed method is successfully applied to identification of the genes that are associated with anticancerdrug sensitivities based on the data collected in the cancer cell line encyclopedia (CCLE) study.

Long non-coding RNA CRYBG3 regulates glycolysis of lung cancer cells by interacting with lactate dehydrogenase A

Cancer cells usually utilize glucose as a carbon source for aerobic glycolysis, a phenomenon known as the Warburg effect. And a high rate of glycolysis has been observed in lung cancer cells. The growing evidence indicates that long non-coding RNAs (lncRNAs) are important players in lung cancer initiation and progression. However, the correlation between lncRNAs and glycolysis remains unclear. In this study, we recognized a lncRNA, LNC CRYBG3, which can interact with lactate dehydrogenase A (LDHA), a vital enzyme of glycolysis, is highly upregulated in both clinical lung cancer tissues and in vitro cultured lung cancer cell lines. A positive correlation between the expression level of LNC CRYBG3 and LDHA expression levels is observed. In another hand, LNC CRYBG3 is a regulator of glycolysis and its overexpression promoted the uptake of glucose and the production of lactate whereas the knockdown of LNC CRYBG3 led to opposite results and suppressed cell proliferation. These results indicated that LNC CRYBG3 might be a novel target for lung cancer treatment.

Modeling small cell lung cancer (SCLC) biology through deterministic and stochastic mathematical models

Mathematical cancer models are immensely powerful tools that are based in part on the fractal nature of biological structures, such as the geometry of the lung. Cancers of the lung provide an opportune model to develop and apply algorithms that capture changes and disease phenotypes. We reviewed mathematical models that have been developed for biological sciences and applied them in the context of small cell lung cancer (SCLC) growth, mutational heterogeneity, and mechanisms of metastasis. The ultimate goal is to develop the stochastic and deterministic nature of this disease, to link this comprehensive set of tools back to its fractalness and to provide a platform for accurate biomarker development. These techniques may be particularly useful in the context of drug development research, such as combination with existing omics approaches. The integration of these tools will be important to further understand the biology of SCLC and ultimately develop novel therapeutics.

Cigarette smoke enhances oncogene addiction to c-MET and desensitizes EGFR-expressing non-small cell lung cancer to EGFR TKIs

Cigarette smoking is one of the leading risks for lung cancer and is associated with the insensitivity of non‐small cell lung cancer (NSCLC) to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, it remains undetermined whether and how cigarette smoke affects the therapeutic efficacy of EGFR TKIs. In this study, our data showed that chronic exposure to cigarette smoke extract (CSE) or tobacco smoke‐derived carcinogen benzo[α]pyrene, B[α]P, but not nicotine‐derived nitrosamine ketone (NNK), reduced the sensitivity of wild‐type EGFR‐expressing NSCLC cells to EGFR TKIs. Treatment with TKIs almost abolished EGFR tyrosine kinase activity but did not show an inhibitory effect on downstream Akt and ERK pathways in B[α]P‐treated NSCLC cells. CSE and B[α]P transcriptionally upregulate c‐MET and activate its downstream Akt pathway, which is not inhibited by EGFR TKIs. Silencing of c‐MET reduces B[α]P‐induced Akt activation. The CSE‐treated NSCLC cells are sensitive to the c‐MET inhibitor crizotinib. These findings suggest that cigarette smoke augments oncogene addiction to c‐MET in NSCLC cells and that MET inhibitors may show clinical benefits for lung cancer patients with a smoking history.

The oleocanthal-based homovanillyl sinapate as a novel c-Met inhibitor

The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) signaling axis has gained considerable attention as an attractive molecular target for therapeutic blockade of cancer. Inspired by the chemical structure of S (-)-oleocanthal, a natural secoiridoid from extra-virgin olive oil with documented anticancer activity against c-Met-dependent malignancies, the research presented herein reports on the discovery of the novel olive-derived homovanillyl sinapate (HVS) as a promising c-Met inhibitor. HVS was distinguished for its remarkable potency against wild-type c-Met and its oncogenic variant in cell-free assays and confirmed by in silico docking studies. Furthermore, HVS substantially impaired the c-Met-mediated growth across a broad spectrum of breast cancer cells, while similar treatment doses had no effect on the non-tumorigenic mammary epithelial cell growth. In addition, HVS caused a dose-dependent inhibition of HGF-induced, but not epidermal growth factor (EGF)-induced, cell scattering in addition to HGF-mediated migration, invasion, and 3-dimensional (3D) proliferation of tumor cell spheroids. HVS treatment effects were mediated via inhibition of ligand-mediated c-Met activation and its downstream mitogenic signaling and blocking molecular mediators involved in cellular motility across different cellular contexts. An interesting feature of HVS is its good selectivity for c-Met and Abelson murine leukemia viral oncogene homolog 1 (ABL1) when profiled against a panel of kinases. Docking studies revealed interactions likely to impart high dual affinity for both ABL1 and c-Met kinases. HVS markedly reduced tumor growth, showed excellent pharmacodynamics, and suppressed cell proliferation and microvessel density in an orthotopic model of triple negative breast cancer. Collectively, the present findings suggested that the oleocanthal-based HVS is a promising c-Met inhibitor lead entity with excellent therapeutic potential to control malignancies with aberrant c-Met activity.

Crizotinib, a MET inhibitor, inhibits growth, migration, and invasion of breast cancer cells in vitro and synergizes with chemotherapeutic agents

MET is a receptor tyrosine kinase known for its pleiotropic effects in tumorigenesis. Dysregulations of MET expression and/or signaling have been reported and determined to be associated with inferior outcomes in breast cancer patients rendering MET a versatile candidate for targeted therapeutic intervention. Crizotinib is a multi-targeted small-molecule kinase inhibitor for MET, ALK, and ROS1 kinases. This study evaluated the anti-proliferative, cytotoxic, anti-migratory, and anti-invasive effects of crizotinib in breast cancer cells in vitro. Cell viability was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) colorimetric assay. In vitro wound-healing assay was used to examine the effect of crizotinib on breast cancer cell migration. The expressions of Ki-67, MET, and phospho-MET receptors were characterized using immunofluorescence staining. Results showed that crizotinib has significant anti-proliferative activity on all mammary tumor cells with IC₅₀ values of 5.16, 1.5, and 3.85 µM in MDA-MB-231, MCF-7, and SK-BR-3 cells, respectively. Crizotinib induced cytotoxic effects in all breast cancer cells examined. Combined treatment of small dose of crizotinib with paclitaxel or doxorubicin exhibited a highly synergistic inhibition of growth of MDA-MB-231 and MCF-7 cells with combination index values <1 while no significant effect was observed in SK-BR-3 cells compared with individual compounds. Treatment with crizotinib demonstrated a remarkable reduction in the expression of Ki-67 protein in all 3 tested cell lines. Crizotinib inhibited migration and invasion of MDA-MB-231 cells in a dose-dependent fashion. Crizotinib reduced MET receptor activation in MDA-MB-231 cells when treated at effective concentrations. In conclusion, crizotinib suppressed proliferation, migration, and invasion of breast cancer cells in vitro. The results of this study demonstrated that combined treatment of crizotinib with chemotherapeutic agents resulted in a synergistic growth inhibition of specific breast cancer cell lines.

Analysis of circulating adipokines in patients newly diagnosed with solid cancer: Associations with measures of adiposity and tumor characteristics

The development and progression of cancer is a complex and multifactorial process and the global prevalence of obesity is markedly increasing. A number of studies have made an association between obesity and increased rates of epithelial tumors. Obesity is associated with altered adipokine levels, potentially contributing to the process of tumor development and metastasis. In the current study, the associations between circulating adipokines and measures of adiposity and tumor characteristics among patients diagnosed with solid malignancies were examined at the time of presentation, and following the administration of chemotherapy. A total of 30 patients with cancer and matched healthy controls were enrolled in the present study. Plasma adipokine levels of hepatocyte growth factor (HGF), adiponectin and leptin were determined using commercially available ELISA kits. At baseline, plasma HGF, adiponectin and leptin levels were not significantly different between patients with cancer and the healthy controls. Circulating HGF levels were significantly associated with the stage of cancer at diagnosis (P=0.044), but lacked a significant association with lymph node status (P=0.194). Plasma adiponectin and leptin levels were not significantly associated with tumor characteristics at the time of diagnosis. Only leptin was positively correlated with the body mass index of patients with cancer (P<0.001). No significant correlations were detected between the evaluated adipokines and measures of visceral obesity, as determined by waist circumference and the waist-hip ratio at presentation. Following administration of chemotherapy, adiponectin was the only adipokine evaluated in the current study that exhibited a significant difference, when compared with baseline plasma levels (P=0.013), and a significant positive correlation between baseline and follow-up circulating levels (P=0.002) among patients with cancer. In addition, there were no significant inter-correlations between circulating adipokines at baseline level and during follow-up in patients with cancer. Collectively, the findings of the current study suggest a lack of diagnostic roles for the adipokines investigated and no significant association with measures of adiposity. Adiponectin may be a potential adipokine to measure in patients with cancer, in order to further assess its prognostic and predictive potential.

Targeted therapy in esophageal cancer

An increasing number of patients are diagnosed with esophageal cancer at an advanced stages, and only a small group of them can benefit from the traditional chemotherapy and radiotherapy. So far, multiple monoclonal antibodies and tyrosine kinase inhibitors have been developed, alone or in combination with traditional therapy, to improve the prognosis of patients with advanced esophageal cancer. This review summarizes the recent advances of targeted therapies against EGFR, HER2, VEGFR and c-MET in esophageal cancer. More clinical trials should be performed to evaluate the efficacy and safety of various targeted therapy regimens. Future basic research should focus on investigating the molecular mechanisms of therapeutic targets in esophageal cancer.

Hypoxia-inducible factor-1 and associated upstream and downstream proteins in the pathophysiology and management of glioblastoma

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with an exceptionally poor patient outcome despite aggressive therapy including surgery, radiation, and chemotherapy. This aggressive phenotype may be associated with intratumoral hypoxia, which probably plays a key role in GBM tumor growth, development, and angiogenesis. A key regulator of cellular response to hypoxia is the protein hypoxia-inducible factor–1 (HIF-1). An examination of upstream hypoxic and nonhypoxic regulation of HIF-1 as well as a review of the downstream HIF-1– regulated proteins may provide further insight into the role of this transcription factor in GBM pathophysiology. Recent insights into upstream regulators that intimately interact with HIF-1 could provide potential therapeutic targets for treatment of this tumor. The same is potentially true for HIF-1–mediated pathways of glycolysis-, angiogenesis-, and invasion-promoting proteins. Thus, an understanding of the relationship between HIF-1, its upstream protein regulators, and its downstream transcribed genes in GBM pathogenesis could provide future treatment options for the care of patients with these tumors.

MET genetic lesions in non-small-cell lung cancer: pharmacological and clinical implications

Lung cancer is the leading cause of death for solid tumors worldwide with an annual mortality of over one million. Lung carcinoma includes a series of different diseases which are roughly divided into two groups based on clinical and histo-pathological features: non-small cell lung cancer (NSCLC), accounting for almost 80% of lung cancer diagnosis and small cell lung cancer (SCLC) responsible for the remaining 20%. The NSCLC molecular profile has been deeply investigated; alterations in several oncogenes, tumor suppressor genes and transcription factors have been detected, mainly in adenocarcinomas. Dissection of such a complex scenario represents a still open challenge for both researchers and clinicians. MET, the receptor for Hepatocyte Growth Factor (HGF), has been recently identified as a novel promising target in several human malignancies, including NSCLC. Deregulation of the HGF/MET signaling pathway can occur via different mechanisms, including HGF and/or MET overexpression, MET gene amplification, mutations or rearrangements. While the role of MET mutations in NSCLC is not yet fully understood, MET amplification emerged as a critical event in driving cell survival, with preclinical data suggesting that MET-amplified cell lines are exquisitely sensitive to MET inhibition. True MET amplification, which has been associated with poor prognosis in different retrospective series, is a relatively uncommon event in NSCLC, occurring in 1-7% of unselected cases. Nevertheless, in highly selected cohorts of patients, such as those harboring somatic mutations of EGFR with acquired resistance to EGFR tyrosine kinase inhibitors, MET amplification can be observed in up to 20% of cases. Preclinical data suggested that a treatment approach including a combination of EGFR and MET tyrosine kinases could be an effective strategy in this setting and led to the clinical investigation of multiple MET inhibitors in combination with anti-EGFR agents. Results from ongoing and future trials will clarify the role of anti-MET molecules for the treatment of NSCLC and will provide insights into the most appropriate timing for their use. The present review recapitulates the current knowledge on the role of MET signaling in NSCLC mainly focusing on its implications in molecular diagnostic approach and on the novel targeted inhibitors.

Therapeutic potential of hepatocyte growth factor against cerebral ischemia (Review)

The effective treatment for cerebral ischemia has not yet been established. Hepatocyte growth factor (HGF) is a potent pleiotropic cytokine that is involved in cell and tissue regeneration, including in the central nervous system. Studies have demonstrated that an exogenous administration of HGF protects brain tissue from ischemic damage. In response to binding to the receptor c-Met, HGF activates the downstream signaling pathways (including the phosphatidylinositol 3-kinase/Akt, Ras/MAPK and signal transducer and activator of transcription pathways) which leads to various cellular responses involved in angiogenesis, glial scar formation, anti-apoptosis and neurogenesis. The purpose of this review is to summarize the present understanding of the therapeutic potential of HGF in cerebral ischemia.

RNA interference targeting hypoxia-inducible factor 1α via a novel multifunctional surfactant attenuates glioma growth in an intracranial mouse model

OBJECT

High-grade gliomas are the most common form of adult brain cancer, and patients have a dismal survival rate despite aggressive therapeutic measures. Intratumoral hypoxia is thought to be a main contributor to tumorigenesis and angiogenesis of these tumors. Because hypoxia-inducible factor 1α (HIF-1α) is the major mediator of hypoxia-regulated cellular control, inhibition of this transcription factor may reduce glioblastoma growth.

METHODS

Using an orthotopic mouse model with U87-LucNeo cells, the authors used RNA interference to knock down HIF-1α in vivo. The small interfering RNA (siRNA) was packaged using a novel multifunctional surfactant, 1-(aminoethyl) iminobis[N-(oleicylcysteinylhistinyl-1-aminoethyl)propionamide] (EHCO), a nucleic acid carrier that facilitates cellular uptake and intracellular release of siRNA. Stereotactic injection was used to deliver siRNA locally through a guide-screw system, and delivery/uptake was verified by imaging of fluorescently labeled siRNA. Osmotic pumps were used for extended siRNA delivery to model a commonly used human intracranial drug-delivery technique, convection-enhanced delivery.

RESULTS

Mice receiving daily siRNA injections targeting HIF-1α had a 79% lower tumor volume after 50 days of treatment than the controls. Levels of the HIF-1 transcriptional targets vascular endothelial growth factor (VEGF), glucose transporter 1 (GLUT-1), c-MET, and carbonic anhydrase-IX (CA-IX) and markers for cell growth (MIB-1 and microvascular density) were also significantly lower. Altering the carrier EHCO by adding polyethylene glycol significantly increased the efficacy of drug delivery and subsequent survival.

CONCLUSIONS

Treating glioblastoma with siRNA targeting HIF-1α in vivo can significantly reduce tumor growth and increase survival in an intracranial mouse model, a finding that has direct clinical implications.

Targeting met mediated epithelial-mesenchymal transition in the treatment of breast cancer

Mesenchymal epithelial transition factor receptor (Met) is a receptor tyrosine kinase that plays a critical role in promoting cancer cell malignant progression. Met is activated by its ligand hepatocyte growth factor (HGF). HGF-dependent Met activation plays an important role in stimulating epithelial-mesenchymal transition (EMT) in tumor cells, resulting in increased tumor cell proliferation, survival, motility, angiogenesis, invasion, and metastasis. The HGF/Met axis has thus attracted great interest as a potential target in the development of novel cancer therapies. In an effort to suppress tumor cell malignant progression, efforts have been made to develop agents capable of inhibiting inhibit Met-induced EMT, including specific Met tyrosine kinase inhibitors, HGF antagonists that interfere with HGF binding to Met, and antibodies that prevent Met activation and/or dimerization. Tocotrienols, a subgroup within the vitamin E family of compounds, display potent anticancer activity that results, at least in part, from inhibition of HGF-dependent Met activation and signaling. The present review will provide a brief summary of the increasing importance of the HGF/Met axis as an attractive target for cancer chemotherapy and the role of tocotrienols in suppressing Met activation, signaling and HGF-induced EMT in breast cancer cells. Evidence provided suggests that γ-tocotrienol therapy may afford significant benefit in the treatment of breast cancers characterized by Met dysregulation.

Collagen triple helix repeat containing 1 (Cthrc1) is an independently prognostic biomarker of non-small cell lung cancers with cigarette smoke

Collagen triple helix repeat containing 1 (Cthrc1) has been recently documented in various malignancies, but its role in non-small cell lung cancer (NSCLC) remains uncertain. In the current study, we investigated the level of Cthrc1 in NSCLC tissues by immunohistochemistry. Results revealed that Cthrc1 overexpression was significantly associated with differentiation (P=0.039), tumor-node-metastasis (TNM) stage (P=0.035), lymph node status (P=0.001), and cigarette smoke (P=0.037). Furthermore, it was shown that patients with high Cthrc1 expression had significantly poorer overall survival (OS) and disease-free survival (DFS; P=0.004 and P=0.010, respectively). Interestingly, high Cthrc1 expression was an independent prognostic factor for both OS and DFS (P=0.010 and P=0.005, respectively) only in NSCLCs with cigarette smoke. These results indicated and suggested that Cthrc1 could be used as a prognostic marker for NSCLC, and it may play an important role in the smoked-related NSCLC.

Olive phenolics as c-Met inhibitors: (-)-Oleocanthal attenuates cell proliferation, invasiveness, and tumor growth in breast cancer models

Dysregulation of the Hepatocyte growth factor (HGF)/c-Met signaling axis upregulates diverse tumor cell functions, including cell proliferation, survival, scattering and motility, epithelial-to-mesenchymal transition (EMT), angiogenesis, invasion, and metastasis. (-)-Oleocanthal is a naturally occurring secoiridoid from extra-virgin olive oil, which showed antiproliferative and antimigratory activity against different cancer cell lines. The aim of this study was to characterize the intracellular mechanisms involved in mediating the anticancer effects of (-)-oleocanthal treatment and the potential involvement of c-Met receptor signaling components in breast cancer. Results showed that (-)-oleocanthal inhibits the growth of human breast cancer cell lines MDA-MB-231, MCF-7 and BT-474 while similar treatment doses were found to have no effect on normal human MCF10A cell growth. In addition, (-)-oleocanthal treatment caused a dose-dependent inhibition of HGF-induced cell migration, invasion and G1/S cell cycle progression in breast cancer cell lines. Moreover, (-)-oleocanthal treatment effects were found to be mediated via inhibition of HGF-induced c-Met activation and its downstream mitogenic signaling pathways. This growth inhibitory effect is associated with blockade of EMT and reduction in cellular motility. Further results from in vivo studies showed that (-)-oleocanthal treatment suppressed tumor cell growth in an orthotopic model of breast cancer in athymic nude mice. Collectively, the findings of this study suggest that (-)-oleocanthal is a promising dietary supplement lead with potential for therapeutic use to control malignancies with aberrant c-Met activity.

Role of c-Met/phosphatidylinositol 3-kinase (PI3k)/Akt signaling in hepatocyte growth factor (HGF)-mediated lamellipodia formation, reactive oxygen species (ROS) generation, and motility of lung endothelial cells

Hepatocyte growth factor (HGF) mediated signaling promotes cell proliferation and migration in a variety of cell types and plays a key role in tumorigenesis. As cell migration is important to angiogenesis, we characterized HGF-mediated effects on the formation of lamellipodia, a pre-requisite for migration using human lung microvascular endothelial cells (HLMVECs). HGF, in a dose-dependent manner, induced c-Met phosphorylation (Tyr-1234/1235, Tyr-1349, Ser-985, Tyr-1003, and Tyr-1313), activation of PI3k (phospho-Yp85) and Akt (phospho-Thr-308 and phospho-Ser-473) and potentiated lamellipodia formation and HLMVEC migration. Inhibition of c-Met kinase by SU11274 significantly attenuated c-Met, PI3k, and Akt phosphorylation, suppressed lamellipodia formation and endothelial cell migration. LY294002, an inhibitor of PI3k, abolished HGF-induced PI3k (Tyr-458), and Akt (Thr-308 and Ser-473) phosphorylation and suppressed lamellipodia formation. Furthermore, HGF stimulated p47(phox)/Cortactin/Rac1 translocation to lamellipodia and ROS generation. Moreover, inhibition of c-Met/PI3k/Akt signaling axis and NADPH oxidase attenuated HGF- induced lamellipodia formation, ROS generation and cell migration. Ex vivo experiments with mouse aortic rings revealed a role for c-Met signaling in HGF-induced sprouting and lamellipodia formation. Taken together, these data provide evidence in support of a significant role for HGF-induced c-Met/PI3k/Akt signaling and NADPH oxidase activation in lamellipodia formation and motility of lung endothelial cells.

Dysregulation of circulating follicular helper T cells in nonsmall cell lung cancer

Nonsmall cell lung cancer (NSCLC) is greatly affected by the dysregulation of the immune system. Circulating follicular helper T cells (Tfh) play critical roles in inducing B-cell activation and producing various cytokines. In the current study, we investigated levels of circulating Tfh in NSCLC. Circulating Tfh and it subtypes were determined by measuring CD3, CD4, CXCR5, CXCR3, and CCR6 in 62 NSCLC patients and 66 healthy controls using flow cytometry. Data presented that percentage of circulating Tfh in the peripheral CD4(+) T cells was significantly increased in NSCLC (14.0%) than in controls (8.7%) (p<0.001). Further analysis revealed that the upregulation of Tfh was contributed by the Th2-Tfh subtype and the Th17-Tfh subtype, whereas the percentage of the Th1-Tfh subtype was significantly decreased in patients. Investigating the clinical stages of the patients demonstrated that prevalence of Tfh was significantly elevated in cases with advanced stages (III: 14.2%; IV: 16.4%) than those with primary stages (I: 10.9%; II: 10.8%). In addition, we analyzed Tfh in patients with different histological types. Results showed that the percentage of circulating Tfh was further upregulated in adenocarcima than squamous cell carcinoma or other types. This study suggests the involvement of circulating Tfh in the pathogenesis and progression of NSCLC, and provides a potential pathway for understanding this disease.

Variance of TNFAIP8 expression between tumor tissues and tumor-infiltrating CD4+ and CD8+ T cells in non-small cell lung cancer

Tumor necrosis factor alpha-induced protein 8 (TNFAIP8) has been recently documented in various malignancies, but its role in non-small cell lung cancer (NSCLC) remains uncertain. In the current study, we investigated the level of TNFAIP8 in NSCLC tissues, adjacent noncancerous lung tissues, healthy lung tissues, CD4+ T cells, and CD8+ T cells by real-time reverse transcription PCR (RT-PCR) and Western blot analysis. Results revealed that the mRNA level of TNFAIP8 was significantly increased in cancer tissue than in healthy lung tissue from donors (p < 0.001). Interestingly, adjacent noncancerous lung tissues also showed higher mRNA level of TNFAIP8 than healthy lung tissue from donors (p < 0.01). Similarly, protein level of TNFAIP8 was elevated in NSCLC tissues and adjacent noncancerous lung tissues. We further analyzed TNFAIP8 expression in CD4+ T cells and CD8+ T cells. Data demonstrated that both mRNA level and protein level were significantly decreased in tumor-infiltrating CD4+ and CD8+ T cells than in peripheral CD4+ and CD8+ T cells. Moreover, patients with advanced stages presented lower protein expression of TNFAIP8 in tumor-infiltrating CD8+ T cells than patients with primary stages (p < 0.05). These results provide evidence that TNFAIP8 plays critical roles in NSCLC and may be used as a therapeutic target for the disease.

Level of plasmacytoid dendritic cells is increased in non-small cell lung carcinoma

In non-small cell lung carcinoma (NSCLC), the immune system fails to eradicate established tumors partly due to the induction of immune tolerance within the tumor microenvironment. Plasmacytoid dendritic cells (pDCs) play critical roles in regulating the immune system. In this study, we investigated pDCs in the peripheral blood of NSCLC. CD4 + CD123 + BDCA2+ pDCs were tested from peripheral blood mononuclear cells in 52 NSCLC patients and 52 healthy controls by flow cytometry. Results revealed that proportion of pDCs was significantly increased in cases than in controls (0.52 ± 0.07% versus 0.21 ± 0.02%, p < 0.001), whereas myeloid dendritic cells (mDCs) did not present any obvious difference between patients and healthy donors (0.25 ± 0.04 % versus 0.18 ± 0.02%, p = 0.120). We further studied pDCs in NSCLC patients with different clinical stages. Data showed that cases with higher stages (III/IV) had elevated level of pDCs than those with lower stages (I/II) (0.65 ± 0.09% versus 0.25 ± 0.07%, p = 0.006). In addition, the amount of pDCs was identified to be associated with squamous cell carcinoma, one of the major subtypes of NSCLC. Interestingly, we observed that smoking patients presented significantly elevated pDCs than those non-smokers (0.63 ± 0.09% versus 0.22 ± 0.05%, p = 0.008). These data suggested that pDCs may be closely involved in the pathogenesis of NSCLC and may predict the progression of the disease.

Combined γ-tocotrienol and Met inhibitor treatment suppresses mammary cancer cell proliferation, epithelial-to-mesenchymal transition and migration

OBJECTIVES

Dysregulation of Met signalling is associated with malignant transformation. Combined treatment has been shown to reduce Met activation and mammary tumour cell proliferation. Experiments here, were conducted to determine mechanisms involved in mediating anti-cancer effects of combined γ-tocotrienol and SU11274 (Met inhibitor) treatment in various mammary cancer cell lines.

MATERIALS AND METHODS

Treatment effects on mouse (+SA) and human (MCF-7, and MDA-MB-231) mammary cancer cell lines, and normal mouse (CL-S1) and human (MCF10A) mammary epithelial cell lines were compared. Cell proliferation and survival were determined by MTT assay and Ki-67 staining; protein expression was determined by western blot analysis. Immunofluorescence staining was also used to characterize expression and localization of multiple epithelial and mesenchymal markers. Cell migration was determined using a wound-healing assay.

RESULTS

Combined treatment with γ-tocotrienol and SU11274 resulted in synergistic inhibition of +SA, MCF-7, and MDA-MB-231, but not CL-S1 or MCF10A cell growth that was associated with reduction in Akt STAT1/5 and NFκB activation and corresponding blockade in epithelial-to-mesenchymal transition, as indicated by increased expression of E-cadherin, β-catenin, and cytokeratins 8/18 (epithelial markers) and corresponding reduction in vimentin (mesenchymal marker) and reduction in cancer cell motility.

CONCLUSIONS

Suggest that combined γ-tocotrienol and Met inhibitor treatment may provide benefit in treatment of breast cancers characterized by aberrant Met activity.

Oncogenic driver mutations in lung cancer

Lung cancer is a heterogeneous and complex disease. Genomic and transcriptomic profiling of lung cancer not only further our knowledge about cancer initiation and progression, but could also provide guidance on treatment decisions. The fact that targeted treatment is most successful in a subset of tumors indicates the need for better classification of clinically related molecular tumor phenotypes based on better understanding of the mutations in relevant genes, especially in those oncogenic driver mutations. EGFR gene mutations, KRAS gene mutations, EML4-ALK rearrangements and altered MET signaling are widely recognized alterations that play important roles in both the biological mechanisms and the clinical sensitivity to treatment in lung cancer. In this article, we reviewed the discovery of the clinical values of these oncogenic driver mutations and the clinical studies revealing the prognostic and predictive values of these biomarkers for clinical sensitivity and resistance to anti-EGFR therapy or other targeted therapies. These form the basis of personalized treatment in lung cancer based on biomarker profiles of individual tumor, leading to therapeutic advancement and betterment.

T-cell immunoglobulin- and mucin-domain-containing molecule 3 gene polymorphisms and prognosis of non-small-cell lung cancer

Lung cancer is the leading cause of death worldwide. Non-small-cell lung cancer (NSCLC) accounts for most of these cases. T-cell immunoglobulin- and mucin-domain-containing molecule 3 (TIM-3) has been established as a negative regulatory molecule and plays a critical role in immune tolerance. Studies have shown that polymorphisms in TIM-3 gene can be associated with various diseases. The aim of this study was to investigate whether polymorphisms in the TIM-3 gene were associated with susceptibility to NSCLC. Three polymorphisms in TIM-3 gene (-1516G/T, -574G/T, and +4259T/G) were identified by polymerase chain reaction-restriction fragment length polymorphism in 432 NSCLC patients and 466 healthy controls. Results showed that frequencies of TIM-3 +4259TG genotype for cases and controls were 10.9 and 4.1 %, respectively; subjects carrying the +4259TG genotype had a 2.81-fold increased risk of NSCLC compared to the wild-type genotype (P < 0.0001). The TIM-3 -1516G/T and -574G/T polymorphisms did not show any correlation with NSCLC. In addition, when analyzing the survival time of NSCLC patients with TIM-3 +4259T/G polymorphism, cases with +4259TG genotype had significantly shorter survival time compared to the wild-type patients (15.2 months vs. 26.7 months, P = 0.007). These results suggested polymorphism in TIM-3 gene is associated with increased susceptibility to NSCLC and could be used as prognostic factor for this malignancy.

Lack of association of C-Met-N375S sequence variant with lung cancer susceptibility and prognosis

BACKGROUND

Previously, we identified a sequence variant (N375S) of c-Met gene, however, its association with lung cancer risk and prognosis remain undefined.

PATIENTS AND METHODS

We investigated the genotype distribution of the c-Met-N375S sequence variant in 206 lung cancer patients and 207 non-cancer controls in the Taiwanese population by DNA sequencing.

RESULTS

Lung cancer patients with variant A/G and G/G genotypes showed 1.08-fold increased cancer risk when compared to patients with the wild-type A/A genotype (95% CI, 0.60-1.91). There were no significant differences in postoperative survival between c-Met-N375S and wild-type patients. In the cell model, the c-Met-N375S cells showed a decrease in cell death upon treatment with MET inhibitor SU11274 compared to wild-type cells.

CONCLUSION

Our data suggest that the c-Met-N375S sequence variant may not play a significant role in cancer susceptibility and the prognosis of lung cancer patients. The correlation with chemoresponse of c-Met-N375S is worth further investigation in patients receiving MET therapy.

The effect of lysyl oxidase polymorphism on susceptibility and prognosis of nonsmall cell lung cancer

Lysyl oxidase (LOX) is a copper-dependent amine oxidase that plays important roles in development and homeostasis of the lungs. The aim of this study was to investigate whether polymorphisms in the LOX gene were associated with susceptibility to nonsmall cell lung cancer (NSCLC). We sequenced the promoter region of LOX gene and tested the previously reported polymorphism 473 G/A in the Han Chinese population. A novel polymorphism, -22 G/C, was identified in the promoter region of LOX. However, it did not show any correlation with NSCLC. Frequencies of the 473AA genotype and 473A allele were significantly higher in the NSCLC cases than in control group (p = 0.004 and p = 0.006, respectively). Further, our results showed that survival time of NSCLC patients with 473AA genotype was significantly shorter compared to the cases carrying 473 G allele (20.0 months vs. 28.0 months, p = 0.011). These data indicate that LOX 473 G/A polymorphism is associated with increased risk of NSCLC and can be a prognostic predictor for this disease.

c-Met, epidermal growth factor receptor, and insulin-like growth factor-1 receptor are important for growth in uveal melanoma and independently contribute to migration and metastatic potential

Uveal melanoma (UM) has a high propensity to develop hepatic metastases. We sought to define the mechanisms required for preferential liver homing and to understand further the biologic behavior of this disease. The Met tyrosine kinase receptor and its ligand hepatocyte growth factor are expressed in hepatocytes. We therefore considered Met/hepatocyte growth factor signaling as a candidate migration/growth factor for UM cells. We further explored the relationship between c-Met and other growth factor receptors prevalent in the liver and their roles in UM metastatic potential. UM cell lines were evaluated for c-Met, epidermal growth factor receptor (EGFR), and insulin-like growth factor-1R (IGF-1R) expression by immunoblotting, and gene amplification by comparative genomic hybridization and fluorescence in-situ hybridization. High c-Met, phosphorylated c-Met, and EGFR expression were noted in two of nine cell lines, independent of IGF-1R levels. Knockdown of c-Met decreased proliferation of high c-Met-expressing UM cells but did not induce apoptosis. Selective inhibitors of EGFR and IGF-1R decreased proliferation and induced apoptosis in UM cells regardless of the expression levels of c-Met, EGFR, and IGF-1R. Although c-Met, EGFR, and IGF-1R play proliferative roles, EGFR and IGF-1R are also critical for UM cell survival. High c-Met/EGFR-expressing cell lines possessed the greatest migration potential. c-Met knockdown and selective inhibitors of c-Met, EGFR, and IGF-1R revealed independent contribution of these receptors to migration. UM can be categorized by levels of c-Met and EGFR expression which are associated with migratory/invasiveness responses to soluble factors present at high levels in the liver. This provides biologic relevance for UM clinical behavior with potential therapeutic implications.

Correlation between MET gene copy number by silver in situ hybridization and protein expression by immunohistochemistry in non-small cell lung cancer

PURPOSE

The MET receptor is involved in the pathogenesis and progression of non-small cell lung cancer (NSCLC). Clinical trials with MET inhibitors in NSCLC are planned with patient selection based on immunohistochemistry (IHC) and/or gene copy number assessment. Therefore, a detailed understanding of relationship between these markers and prognosis is essential.

METHODS

This study included tumors from 189 patients with NSCLC who underwent pulmonary resection (median follow-up, 5.3 years). MET expression was evaluated by IHC on tissue microarrays and scored according to hybrid (H) score (range: 0-400) and by scoring system used in the MetMAb trial (≥ 50% of cells with moderate or strong staining). MET gene copy number was assessed by silver in situ hybridization (n =140 patients).

RESULTS

Median MET IHC H score was 60 (range: 0-400; n =174). There were no associations between clinical and pathological characteristics, disease-free survival, and overall survival according to median value (p =0.36 and p =0.38, respectively), or other cut-points. According to MetMAb scoring criteria, IHC positivity rate was 25%, again with no associations to clinicopathological features or survival. In 140 tumors evaluable for MET copy number, 3 (2.1%) showed gene amplification and 14 (10%) had tumors with average of 5 or more copies per nucleus. There were no associations of MET copy number with clinical characteristics, disease-free survival, or overall survival with any analyzed cut-points. Correlation between MET copy number and protein expression was significant (Pearson's r =0.42, p < 0.0001).

CONCLUSIONS

There is a significant correlation between MET protein expression and MET gene copy number in operable NSCLC, but neither is associated with prognosis.

A novel classification of lung cancer into molecular subtypes

The remarkably heterogeneous nature of lung cancer has become more apparent over the last decade. In general, advanced lung cancer is an aggressive malignancy with a poor prognosis. The discovery of multiple molecular mechanisms underlying the development, progression, and prognosis of lung cancer, however, has created new opportunities for targeted therapy and improved outcome. In this paper, we define "molecular subtypes" of lung cancer based on specific actionable genetic aberrations. Each subtype is associated with molecular tests that define the subtype and drugs that may potentially treat it. We hope this paper will be a useful guide to clinicians and researchers alike by assisting in therapy decision making and acting as a platform for further study. In this new era of cancer treatment, the 'one-size-fits-all' paradigm is being forcibly pushed aside-allowing for more effective, personalized oncologic care to emerge.

Inhibition of fatty acid synthase attenuates CD44-associated signaling and reduces metastasis in colorectal cancer

Fatty acid synthase (FASN) and ATP-citrate lyase, key enzymes of de novo lipogenesis, are significantly upregulated and activated in many cancers and portend poor prognosis. Even though the role of lipogenesis in providing proliferative and survival advantages to cancer cells has been described, the impact of aberrant activation of lipogenic enzymes on cancer progression remains unknown. In this study, we found that elevated expression of FASN is associated with advanced stages of colorectal cancer (CRC) and liver metastasis, suggesting that it may play a role in progression of CRC to metastatic disease. Targeted inhibition of lipogenic enzymes abolished expression of CD44, a transmembrane protein associated with metastases in several cancers including CRC. In addition, inhibition of lipogenic enzymes and reduced expression of CD44 attenuated the activation of MET, Akt, FAK, and paxillin, which are known to regulate adhesion, migration, and invasion. These changes were consistent with an observed decrease in migration and adhesion of CRC cells in functional assays and with reorganization of actin cytoskeleton upon FASN inhibition. Despite the modest effect of FASN inhibition on tumor growth in xenografts, attenuation of lipogenesis completely abolished establishment of hepatic metastasis and formation of secondary metastasis. Together, our findings suggest that targeting de novo lipogenesis may be a potential treatment strategy for advanced CRC.

Interleukin-4 -590T/C polymorphism influences the susceptibility to nonsmall cell lung cancer

Lung cancer is the leading cause of cancer mortality worldwide. Nonsmall cell lung cancer (NSCLC) accounts for most of these cases. Interleukin 4 (IL-4) is a typical pleiotropic T helper 2 cytokine and plays crucial roles in tumor immunology. IL-4 gene -590T/C polymorphism has been shown to be associated with different autoimmune diseases and cancers. The present study evaluated the correlation between this polymorphism and the susceptibility to NSCLC in the Chinese population. The IL-4 variant -590T/C was detected by polymerase chain reaction-restriction fragment length polymorphism in 1072 NSCLC cases and 1126 age-matched healthy controls. Data were analyzed using the Chi-square test. Results showed that frequencies of IL-4 -590 TC, CC genotype, and -590 C allele were significantly lower in patients with NSCLC than in healthy controls (odds ratio [OR]=0.77, 95% confidence interval [CI] 0.64-0.93, p=0.006; OR=0.54, 95% CI 0.38-0.76, p=0.0004; and OR=0.72, 95% CI 0.62-0.83, p=1.1 × 10(-5), respectively). Our data suggest that the -590T/C polymorphism of the IL-4 gene is associated with a decreased susceptibility to NSCLC.

γ-Tocotrienol inhibits HGF-dependent mitogenesis and Met activation in highly malignant mammary tumour cells

OBJECTIVES

  Aberrant Met signalling is associated with aggressive cancer cell phenotypes. γ-tocotrienol displays potent anti-cancer activity that is associated with suppression of HER/ErbB receptor signalling. Experiments were conducted to investigate the effects of γ-tocotrienol treatment on HGF-dependent +SA mammary tumour cell proliferation, upon Met activation.

MATERIALS AND METHODS

  The +SA cells were maintained in serum-free defined media containing 10 ng/ml HGF as the mitogen. Cell viability was determined using the MTT assay, western blot analysis was used to measure protein expression, and Met expression and activation were determined using immunofluorescent staining.

RESULTS AND CONCLUSIONS

  Treatment with γ-tocotrienol or Met inhibitor, SU11274, significantly inhibited HGF-dependent +SA cell replication in a dose-responsive manner. Treatment with 4 μmγ-tocotrienol reduced both total Met levels and HGF-induced Met autophosphorylation. In contrast, similar treatment with 5.5 μm SU11274 inhibited HGF-induced Met autophosphorylation, but had no effect on total Met levels. Combined treatment with subeffective doses of γ-tocotrienol (2 μm) and SU11274 (3 μm) resulted in significant inhibition of +SA cell expansion compared to treatment with individual agents alone. These findings show, for the first time, the inhibitory effects of γ-tocotrienol on Met expression and activation, and strongly suggest that γ-tocotrienol treatment may provide significant health benefits in prevention and/or treatment of breast cancer, in women with deregulated HGF/Met signalling.

Claudin-7 inhibits human lung cancer cell migration and invasion through ERK/MAPK signaling pathway

Tight junctions are the most apical component of the junctional complex critical for epithelial cell barrier and polarity functions. Although its disruption is well documented during cancer progression such as epithelial-mesenchymal transition, molecular mechanisms by which tight junction integral membrane protein claudins affect this process remain largely unknown. In this report, we found that claudin-7 was normally expressed in bronchial epithelial cells of human lungs but was either downregulated or disrupted in its distribution pattern in lung cancer. To investigate the function of claudin-7 in lung cancer cells, we transfected claudin-7 cDNA into NCI-H1299, a human lung carcinoma cell line that has no detectable claudin-7 expression. We found that claudin-7 expressing cells showed a reduced response to hepatocyte growth factor (HGF) treatment, were less motile, and formed fewer foot processes than the control cells did. In addition, cells transfected with claudin-7 dramatically decreased their invasive ability after HGF treatment. These effects were mediated through the MAPK signaling pathway since the phosphorylation level of ERK1/2 was significantly lower in claudin-7 transfected cells than in control cells. PD98059, a selective inhibitor of ERK/MAPK pathway, was able to block the motile effect. Claudin-7 formed stable complexes with claudin-1 and -3 and was able to recruit them to the cell-cell junction area in claudin-7 transfected cells. When control and claudin-7 transfected cells were inoculated into nude mice, claudin-7 expressing cells produced smaller tumors than the control cells. Taken together, our study demonstrates that claudin-7 inhibits cell migration and invasion through ERK/MAPK signaling pathway in response to growth factor stimulation in human lung cancer cells.

The role of adiponectin (ADIPOQ) gene polymorphisms in the susceptibility and prognosis of non-small cell lung cancer

To study the role of the adiponectin (ADIPOQ) gene single-nucleotide polymorphism (SNP) in the susceptibility and prognosis for non-small cell lung cancer (NSCLC), we recruited 344 patients with NSCLC, of which 141 had undergone surgical resection and post-surgery follow up. For controls, there were 264 healthy volunteers for the control group, matched in age and sex with the NSCLC patients. Genotyping of SNPs in the ADIPOQ gene, namely, rs266729 (11365C>G); rs822395 (4034A>C); rs822396 (3964A>G); rs2241766 (+45T>G) were performed. Of all SNPs in the ADIPOQ gene, only the TT genotype and T allele frequency of the rs2241766 were more prevalent in NSCLC subjects than in controls. The TT genotype of rs2241766 was significantly associated with susceptibility to NSCLC before and after adjustment for age, sex, body mass index, and smoking status. In the survival analyses of subjects receiving surgical resection, only the SNPs of rs2241766 were significantly related to overall survival of NSCLC. Our results suggest that the SNP rs2241766 of the ADIPOQ gene may determine both susceptibility to NSCLC, and the prognosis for those who underwent surgical treatment.